Hair straightening emulsion

Abstract

An improved highly alkaline hair straightening emulsion and a two component system for preparing the emulsion are provided. The emulsion employs a combination of strong nitrogenous organic base and alkali metal hydroxide in the presence of an alkaline earth metal cation. Neither the amount of the alkali metal hydroxide nor the amount of organic base present in the emulsion is sufficient by itself to effectively permanently straighten naturally curly hair. Alkaline earth metal hydroxides are characteristically ineffective as permanent hair straighteners. However, surprisingly, the combination is effective for achieving permanent straightening of hair within a treatment time of not more than about 30 minutes. In use, the emulsion also substantially avoids scalp skin irritation. Also, hair discoloration and hair breakage are minimized.

What is claimed is: 
     
       1. A highly alkaline emulsion for permanently straightening naturally curly hair on the scalp of a user through direct contact of said emulsion with said hair, said emulsion having an oil phase and an aqueous phase and containing a combination of three chemical bases one of which is a water-soluble nitrogenous organic base, a second of which is a water-soluble alkali metal hydroxide, and a third of which is a water-soluble alkaline earth metal hydroxide, said emulsion comprising: (a) said nitrogenous organic base being present in said emulsion in an amount that is less than about 2 weight percent calculated as free organic base and based on total weight of said emulsion but said amount being insufficient to produce substantially complete permanent hair straightening in a hair contact time period of about 30 minutes when said nitrogenous organic base is used as the sole said chemical base in said emulsion, said nitrogenous organic base being characterized by having: (1) a pK a  value of at least about 12, and   (2) in its molecular structure a carbon atom that is: doubly bonded to a first nitrogen atom,   singly bonded to a second nitrogen atom, and also,   singly bonded to either another carbon atom or to a third nitrogen atom, said nitrogenous organic base being selected from the group consisting of guanidines and acetamidines,         (b) said alkali metal hydroxide being present in said emulsion in an amount that is less than about 1 weight percent calculated as hydroxide and based on total weight of said emulsion but said amount being insufficient to produce substantially complete permanent hair straightening in a hair contact time period of about 30 minutes when said alkali metal hydroxide is used as the sole said chemical base in said emulsion, and   (c) said alkaline earth metal hydroxide being initially present as said emulsion is formed, said alkaline earth metal hydroxide being inoperative for the purpose of producing substantially complete permanent hair straightening in a hair contact time period of about 30 minutes when said alkaline earth metal hydroxide is used as the sole said chemical base in said emulsion,   (d) lipophilic oleaginous material,   (e) emulsifier, and   (f) water,   said emulsion having a pH in the range of about 11.5 to about 14 but containing respective amounts of each of said nitrogenous organic base, said alkali metal hydroxide and said alkaline earth metal hydroxide such that said emulsion produces a substantially complete permanent straightening of said user's hair when in contact therewith for a contact time period that is not longer than about 30 minutes.   
     
     
       2. The emulsion of claim 1 wherein on a 100 weight percent total emulsion basis: (a) the quantity of said lipophilic oleaginous material is in the range of about 5 to about 60 weight percent,   (b) the quantity of said emulsifier is in the range of about 0.01 to about 25 weight percent, and   (c) the quantity of said water is in the range of about 35 to about 50 weight percent.   
     
     
       3. The emulsion of claim 1 wherein said nitrogenous organic base is produced in situ through hydrolysis of a dissolved, water-soluble salt of said nitrogenous organic base, said organic base salt being characterized by being hydrolyzed in water at 25° C., ambient pressure, and a pH value that is about equal to said pK a  value. 
     
     
       4. The emulsion of claim 3 wherein said salt of said nitrogenous organic salt is guanidine carbonate in an amount of about 10 to about 20 weight percent based on total weight of said emulsion. 
     
     
       5. The emulsion of claim 3 wherein said emulsion is prepared by admixing together an activator component with a cream emulsion component, (a) said activator component comprises on a 100 weight percent total activator component basis: about 10 to about 20 weight percent of said dissolved water-soluble salt of said nitrogenous organic base, and, correspondingly,   about 80 to about 90 weight percent of said water, and     (b) said cream emulsion component comprises on a 100 weight percent total cream emulsion component basis: about 0.6 to about 1.6 weight percent of said alkali metal hydroxide,   about 2 to about 3.5 weight percent of said alkaline earth metal hydroxide, and   about 5 to about 65 weight percent of said lipophilic oleaginous material,   about 0.01 to about 25 weight percent of said emulsifier, and   about 35 to about 60 weight percent of said water; the relative proportions of each of said activator and said cream emulsion used in said admixing being such that said emulsion is produced.       
     
     
       6. The emulsion of claim 5 wherein based upon the total weight of the activator component and the cream emulsion component used in forming said emulsion: (a) the quantity of said nitrogenous organic base that is present in said emulsion ranges from about 0.9 to about 2 weight calculated as free organic base,   (b) the quantity of said alkali metal hydroxide that is present in said emulsion ranges from about 0.5 to about 1 weight percent calculated as hydroxide, and   (c) the quantity of said alkaline earth metal hydroxide initially present ranges from about 1.5 to about 3 weight percent calculated as hydroxide.   
     
     
       7. The emulsion of claim 1 wherein on a 100 weight percent total emulsion basis: (a) the quantity of said lipophilic oleaginous material is in the range of about 5 to about 60 weight percent,   (b) the quantity of said emulsifier is in the range of about 0.01 to about 25 weight percent, and   (c) the quantity of said water is in the range of about 35 to about 50 weight percent.   
     
     
       8. The emulsion of claim 1 wherein said nitrogenous organic base is produced in situ in the presence of said water-soluble alkaline earth metal hydroxide whereby there is further produced in situ a substantially water-insoluble dispersed alkaline earth metal salt having an anion that is derived from the anion of said water-soluble salt of said nitrogenous organic base. 
     
     
       9. The emulsion of claim 8 wherein the anion of said water-soluble salt of said nitrogenous organic base is selected from the group consisting of carbonate, sulfate, sulfite, phosphite, fluoride, oxalate, tartrate, laurate, stearate, alginate and mixtures thereof. 
     
     
       10. The emulsion of claim 1 wherein said alkaline earth metal comprises calcium. 
     
     
       11. The emulsion of claim 1 wherein said alkali metal is selected from the group consisting of lithium, sodium and potassium. 
     
     
       12. The emulsion of claim 11 wherein said alkali metal comprises lithium. 
     
     
       13. The emulsion of claim 1 wherein said lipophilic oleaginous material is selected from the group consisting of petrolatum, mineral oil, mineral jelly, lanolin, water-insoluble silicones, and mixtures thereof. 
     
     
       14. The emulsion of claim 1 which additionally contains a hair conditioning effective amount of a hair conditioner. 
     
     
       15. The emulsion of claim 14 wherein said hair conditioner is selected from the group consisting of water-dispersible monomeric quaternary ammonium compounds containing a long chain aliphatic group having from about 20 to about 24 carbon atoms inclusive and salts thereof, quaternary nitrogen containing polymers and salts thereof, and mixtures thereof. 
     
     
       16. The emulsion of claim 15 wherein hair conditioner is selected from the group consisting of behenyl trimethylammonium methosulfate, behenyl trimethylammonium chloride and mixtures thereof. 
     
     
       17. The emulsion of claim 1 wherein at least a component of each of said lipophilic oleaginous organic material and said emulsifier are each also present in said activator component. 
     
     
       18. The emulsion of claim 1 wherein said emulsifier comprises on a 100 weight percent total emulsion basis: (a) about 2 to about 20 weight percent of a lipophilic nonionic emulsifier, and   (b) about 0.01 to about 10 weight percent of a hydrophilic emulsifier.   
     
     
       19. The emulsion of claim 18 wherein said lipophilic nonionic emulsifier is selected from the group consisting of fatty alcohols derived from fatty acids containing about 12 to about 24 carbon atoms and adducts of said fatty alcohols with alkylene oxides containing at least two and less than four carbon atoms per starting alkylene oxide molecule, and mixtures thereof. 
     
     
       20. The emulsion of claim 18 wherein said hydrophilic emulsifier is selected from the group consisting of amphoteric surfactants, zwitterionic surfactants, nonionic surfactants, anionic surfactants and mixtures thereof. 
     
     
       21. A two component kit for preparing a highly alkaline emulsion useful for permanently straightening naturally curly hair, said kit comprising an activator component and a cream emulsion component, (a) said activator component comprising on a 100 weight percent total activator component basis: about 10 to about 20 weight percent of a dissolved water-soluble salt of a water-soluble nitrogenous organic base, said nitrogenous organic base being characterized by having: (1) a pK a  value of at least about 12, and   (2) in its molecular structure a carbon atom that is: doubly bonded to a first nitrogen atom,   singly bonded to a second nitrogen atom, and also,   singly bonded to either another carbon atom or to a third nitrogen atom,       said nitrogenous organic base being selected from the group consisting of guanidines and acetamidines, and, correspondingly,   about 80 to about 90 weight percent of water, and     (b) said cream emulsion component comprising on a 100 weight percent total emulsion cream component basis: about 0.5 to about 1.6 weight percent of an alkali metal hydroxide,   about 2 to about 3.5 weight percent of an alkaline earth metal hydroxide, and   about 5 to about 65 weight percent of a lipophilic oleaginous material,   about 0.01 to about 25 weight percent of an emulsifier, and   about 35 to about 60 weight percent of water; the amount of said activator component relative to the amount of said cream emulsion component in said kit being such that, when said activator component is admixed with said cream emulsion, said emulsion is produced.       
     
     
       22. The emulsion of claim 1 wherein said nitrogenous organic base is selected from the group consisting of a) guanidine;   b) hydrated guanidine;   c) guanidine substituted with 1-5 substituents selected from the group consisting of alkyl, carboxyalkyl, hydroxyalkyl, amino and alkylamino; and mixtures thereof.     
     
     
       23. The emulsion of claim 22 wherein said nitrogenous organic base comprises guanidine, hydrated guanidine or mixtures thereof. 
     
     
       24. The emulsion of claim 1 wherein said nitrogenous organic base is selected from the group consisting of a) acetamidine;   b) hydrated acetamidine;   c) acetamidine substituted on the terminal carbon atom with a substituent selected from the group consisting of alkyl, amino and alkylamino; and mixtures thereof.     
     
     
       25. The emulsion of claim 24 wherein said nitrogenous organic base comprises acetamidine. 
     
     
       26. The method of claim 1 wherein, in said emulsion, said alkali metal hydroxide comprises lithium hydroxide, said alkaline earth metal hydroxide comprises calcium hydroxide and said organic base comprises guanidine, hydrated guanidine and mixtures thereof.